Tetrahydropyridine derivatives, their preparation and their use as cell proliferation inhibitors

ABSTRACT

A compound of the formula (I) wherein A, R 1 , R 2  and X have the meanings defined in the specification, process of manufacturing such as compound and a pharmaceutical composition with HDAC inhibitor activity and anti-cell proliferation activity containing such a compound.

[0001] The invention relates to tetrahydropyridine derivatives, orpharmaceutically-acceptable salts thereof, which possessanti-cell-proliferation activity such as anti-cancer activity and areaccordingly useful in methods of treatment of the human or animal body.The invention also relates to processes for the manufacture of saidtetrahydropyridine derivatives, to pharmaceutical compositionscontaining them and to their use in the manufacture of medicaments ofuse in the production of an anti-cell-proliferation effect in awarm-blooded animal such as man.

BACKGROUND OF THE INVENTION

[0002] Transcriptional regulation is a major event in celldifferentiation, proliferation, and apoptosis. Transcriptionalactivation of a set of genes determines cell destination and for thisreason transcription is tightly regulated by a variety of factors. Oneof its regulatory mechanisms involved in the process is an alteration inthe tertiary structure of DNA, which affects transcription by modulatingthe accessibility of transcription factors to their target DNA segments.Nucleosomal integrity is regulated by the acetylation status of the corehistones. In a hypoacetylated state, nucleosomes are tightly compactedand thus are nonpermissive for transcription. On the other hand,nucleosomes are relaxed by acetylation of the core histones, with theresult being permissiveness to transcription. The acetylation status ofthe histones is governed by the balance of the activities of histoneacetyl transferase (HAT) and histone deacetylase (HDAC). Recently, HDACinhibitors have been found to arrest growth and apoptosis in severaltypes of cancer cells, including colon cancer, T-cell lymphoma, anderythroleukemic cells. Given that apoptosis is a crucial factor forcancer progression, HDAC inhibitors are promising reagents for cancertherapy as effective inducers of apoptosis (Koyama, Y., et al., Blood 96(2000) 1490-1495).

[0003] Several structural classes of HDAC inhibitors have beenidentified and are reviewed in Marks, P. M., J. Natl. Cancer Inst. 92(2000) 1210-1216. More specifically, WO 98/55449 and U.S. Pat. No.5,369,108 report alkanoyl hydroxamates with HDAC inhibitory activity.

[0004] It has now been found that certain tetrahydropyridine derivativespossess anti-cell-proliferation properties which are more potent thanthose in the aforementioned references. These properties are due to HDACinhibition.

DESCRIPTION OF THE INVENTION

[0005] According to the invention there is provided a tetrahydropyridinederivative of the formula I

[0006] (a) denotes a phenyl group which may be unsubstituted orsubstituted with 1, 2 or 3 substituents independently selected from ahalogen atom, an (1-4C)alkyl-, trifluoromethyl-, hydroxy-,(1-4C)alkoxy-, benzyloxy-, (1-3C)alkylenedioxy-, nitro-, amino-,(1-4C)allylamino-, di[(1-4C)alkyl]-amino-, (1-4C)alkanoyl-amino-, or aphenyl group, which may be unsubstituted or substituted by 1, 2, or 3substituents independently selected from a chlorine atom, an(1-4C)alkyl-, trifluoromethyl-, hydroxy-, (1-4C)alkoxy-,(1-3C)alkylenedioxy-, nitro-, amino-, (1-4C)alkylamino-,di[(1-4C)alkyl]amino-, and an (1-4C)alkanoylamino group, or

[0007] (b) denotes an indolyl group which may be unsubstituted orsubstituted with 1, 2 or 3 substituents independently selected from ahalogen atom, an (1-4C)alkyl-, trifluoromethyl-, hydroxy-,(1-4C)alkoxy-, benzyloxy-, (1-3C)alkylenedioxy-, nitro-, amino-,(1-4C)alkylamino-, di[(1-4C)alkyl]amino-, or an(1-4C)alkano-ylamino-group,

[0008] R¹ and R² are the same as or different from each other and are ahydrogen atom, a (1-4C)alkyl-, a trifluoromethyl group, or an arylgroup,

[0009] X is a straight chain alkylene group comprising 5, 6, or 7 carbonatoms, wherein one CH₂ group may be replaced by an oxygen or a sulfuratom, or wherein 2 carbon atoms form a C═C double bond, and which iseither unsubstituted or substituted by one or two substituents selectedfrom (1-4C)alkyl and halogen atoms,

[0010] their enantiomers, diastereoisomers, racemates and mixturesthereof and pharmaceutically acceptable salts.

[0011] A suitable value for a substituent when it is a halogen atom is,for example, fluoro, chloro, bromo and iodo; when it is (1-4C)alkyl is,for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl,sec-butyl; when it is (1-4C)alkoxy is, for example, methoxy, ethoxy,propoxy, isopropoxy or butoxy; when it is (1-4C)alkylamino is, forexample, methylamino, ethylamino or propylamino; when it isdi-[(1-4C)alkyl]amino is, for example, dimethylamino,N-ethyl-N-methylamino, diethylamino, N-methyl-N-propylamino ordipropylamino; when it is (1-4C)alkanoylamino is, for example,formylamido, acetamido, propionamido or butyramido; and when it is(1-3C)alkylenedioxy is, for example, methylenedioxy, ethylenedioxy orpropylenedioxy.

[0012] A suitable pharmaceutically-acceptable salt of atetrahydropyridine derivative of the invention is, for example, anacid-addition salt with, for example, an inorganic or organic acid, forexample hydrochloric, hydrobromic, sulphuric, phosphoric,trifluoroacetic, citric or maleic acid.

[0013] The annulated tetrahydropyridine ring systems are preferably3,4-dihydro-1H-isoquinoline or 1,3,4,5-tetrahydro-pyrido[4,3-b]indole or1,3,4,9-tetrahydro-β-carboline.

[0014] Preferred compounds of the invention are tetrahydropyridinederivatives of the formula I

[0015] is a phenyl group which may be unsubstituted or substituted with1 or 2 substituents independently chosen from hydroxy-, (1-4C)alkoxy,benzyloxy, or a phenyl group,

[0016] is an indolyl group which may be unsubstituted or substitutedwith a halogen atom,

[0017] R¹ and R² are the same as or different from each other and are ahydrogen atom, a (1-4C)alkyl-, a trifluoromethyl group or a phenylgroup,

[0018] X is a straight chain alkylene group comprising 5, 6, or 7 carbonatoms, wherein one CH₂ group may be replaced by an oxygen or a sulfuratom, or wherein 2 carbon atoms form a C═C double bond, and which iseither unsubstituted or substituted by one or two substituents selectedfrom a methyl group, fluorine, or chlorine atoms,

[0019] their enantiomers, diastereoisomers, racemates and mixturesthereof and pharmaceutically acceptable salts.

[0020] Preparation of the Compounds of the Invention

[0021] The tetrahydropyridine derivatives of the formula I, or apharmaceutically-acceptable salt thereof, may be prepared by any processknown to be applicable to the preparation of chemically-relatedcompounds. Such processes, when used to prepare a tetrahydropyridinederivative of the formula I, or a pharmaceutically-acceptable saltthereof, are provided as a further feature of the invention and areillustrated by the following representative examples in which, unlessotherwise stated, A, R¹, R² and X have any of the meanings definedhereinbefore. Necessary starting materials may be obtained by standardprocedures of organic chemistry. The preparation of such startingmaterials is described within the accompanying non-limiting examples.Alternatively necessary starting materials are obtainable by analogousprocedures to those illustrated which are within the ordinary skill ofan organic chemist.

[0022] (a) One preferred method for the preparation of compounds of theformula I is the deprotection of compounds of the formula II

[0023] wherein Y is a suitable protecting group. Compounds of theformula II are new and included in the present invention.

[0024] Suitable protecting groups are the benzyl-, p-methoxybenzyl-,tert.butyloxycarbonyl-, trityl-, or silyl groups such as thetrimethylsilyl- or dimethyl-tertbutylsilyl-group. The reactions carriedout depend on the type of the protecting group. When the protectinggroup is a benzyl- or p-methoxybenzyl group, the reaction carried out isa hydrogenolysis in an inert solvent such as an alcohol like methanol orethanol, in the presence of a noble metal catalyst such as palladium ona suitable carrier such as carbon, barium sulfate, or barium carbonate,at ambient temperature and pressure. When the protecting group is thetertbutyloxycarbonyl-, trityl-, or a silyl group such as thetrirnethylsilyl- or dimethyl-tert.butylsilyl-group, the reaction iscarried out in the presence of acids at a temperature between −20° C.and 60° C., preferably between 0° C. and ambient temperature. The acidmay be a solution of hydrochloric acid in an inert solvent such asdiethyl ether or dioxane, or trifluoro acetic acid in dichloromethane.When the protecting group is a silyl group such as the trimethylsilyl ordimethyl-tert.butylsilyl group, the reaction is carried out in thepresence of a fluoride source such as sodium fluoride or tetrabutylammonium fluoride in an inert solvent such as dichloromethane.

[0025] The tetrahydropyridine derivative of the formula I may beobtained from this process in the form of the free base or alternativelyit may be obtained in the form of a salt. When it is desired to obtainthe free base from the salt, the salt may be treated with a suitablebase, for example, an alkali or alkaline earth metal carbonate orhydroxide, for example sodium carbonate, potassium carbonate, calciumcarbonate, sodium hydroxide or potassium hydroxide.

[0026] Compounds of the formula II are obtained by the reaction of atetrahydropyridine of the formula III

[0027] wherein A, R¹ and R² have the meaning defined hereinbefore, witha compound of formula IV

Z-X—CONH—O—Y  (IV)

[0028] wherein Z is a displaceable group and X and Y have the meaningdefined hereinbefore, in the absence or presence of a suitable base.

[0029] A suitable displaceable group Z is, for example, a halogeno, orsulphonyloxy group, for example a chloro, bromo, methanesulphonyloxy ortoluene-p-sulphonyloxy group. A suitable base is, for example, anorganic amine base such as, for example, pyridine, 2,6-lutidine,collidine, 4-dimethylaminopyridine, triethylamine, morpholine,N-methylmorpholine or diazabicyclo[5.4.0]undec-7-ene, or, for example,an alkali or alkaline earth metal carbonate or hydroxide, for examplesodium carbonate, potassium carbonate, calcium carbonate, sodiumhydroxide or potassium hydroxide.

[0030] The reaction is conveniently carried out in the presence of asuitable inert solvent or diluent, for example an alkanol or ester suchas methanol, ethanol, isopropanol or ethyl acetate, a halogenatedsolvent such as methylene chloride, chloroform or carbon tetrachloride,an ether such as tetrahydrofuran or 1,4-dioxan, an aromatic solvent suchas toluene, or a dipolar aprotic solvent such as N,N-dimethylformamide,N,N-dimethylacetamide, N-ethylpyrrolidin-2-one or dimethylsulphoxide.The reaction is conveniently carried out at a temperature in the range,for example, 10 to 250° C., preferably in the range 40-200° C.

[0031] (b) Another preferred method for the preparation of compounds ofthe formula I involves the reaction of compounds of the formula V

[0032] wherein A, R¹, R², and X have the meaning defined hereinbefore,with hydroxylamine. This reaction typically involves a two-step one-potprocedure. In the first step, the carboxylate of the formula V becomesactivated. This reaction is carried out in an inert solvent or diluent,for example, in dichloromethane, dioxane, or tetrahydrofuran, in thepresence of an activating agent. A suitable reactive derivative of anacid is, for example, an acyl halide, for example an acyl chlorideformed by the reaction of the acid and an inorganic acid chloride, forexample thionyl chloride; a mixed anhydride, for example an anhydrideformed by the reaction of the acid and a chloroformate such as isobutylchloroformate; an active ester, for example an ester formed by thereaction of the acid and a phenol such as pentafluorophenol, an estersuch as pentafluorophenyl trifluoroacetate or an alcohol such asmethanol, ethanol, isopropanol, butanol or N-hydroxybenzotriazole; anacyl azide, for example an azide formed by the reaction of the acid andan azide such as diphenylphosphoryl azide; an acyl cyanide, for examplea cyanide formed by the reaction of an acid and a cyanide such asdiethylphosphoryl cyanide; or the product of the reaction of the acidand a carbodiimide such as dicyclohexylcarbodiimide. The reaction iscarried out between −30° C. and 60° C., conveniently at or below 0° C.In the second step, hydroxylamine is added to the solution, at thetemperature used for the activation, and the temperature is slowlyadjusted to ambient temperature.

[0033] Compounds of the formula V are prepared from compounds of theformula VI

[0034] wherein A, R¹, R², and X have the meaning defined hereinbeforeand R³ is an alkyl group, for example, a methyl, ethyl, or tert. butylgroup or benzyl group, by hydrolysis. The conditions under which thehydrolysis is carried out depend on the nature of the group R³. When R³is a methyl or ethyl group, the reaction is carried out in the presenceof a base, for example, lithium hydroxide, sodium hydroxide, orpotassium hydroxide in an inert solvent or diluent, for example, inmethanol or ethanol. When R³ is the tert.butyl group, the reaction iscarried out in the presence of an acid, for example, a solution ofhydrochloric acid in an inert solvent such as diethyl ether or dioxane,or trifluoro acetic acid in dichloromethane. When R³ is the benzylgroup, the reaction is carried out by hydrogenolysis in the presence ofa noble metal catalyst such as Palladium on a suitable carrier, such ascarbon. Compounds of the formula VI are prepared from compounds of theformula III

[0035] wherein A, R¹, and R² have the meaning defined hereinbefore, byreaction of compounds of the formula VII

Z-X—COO—R³  (VI)

[0036] wherein Z, X, and R³ have the meaning defined hereinbefore, inthe absence or presence of a suitable base.

[0037] A suitable base is, for example, an organic amine base such as,for example, pyridine, 2,6-lutidine, collidine, 4-dimethylaminopyridine,triethylamine, morpholine, N-methylmorpholine ordiazabicyclo[5.4.0]undec-7-ene, or, for example, an alkali or alkalineearth metal carbonate or hydroxide, for example sodium carbonate,potassium carbonate, calcium carbonate, sodium hydroxide or potassiumhydroxide.

[0038] The reaction is conveniently carried out in the presence of asuitable inert solvent or diluent, for example an alkanol or ester suchas methanol, ethanol, isopropanol or ethyl acetate, a halogenatedsolvent such as methylene chloride, chloroform or carbon tetrachloride,an ether such as tetrahydrofuran or 1,4-dioxan, an aromatic solvent suchas toluene, or a dipolar aprotic solvent such as N,N-dimethylformamide,N,N-dimethylacetamide, N-ethylpyrrolidin-2-one or dimethylsulphoxide.The reaction is conveniently carried out at a temperature in the range,for example, 10 to 250° C., preferably in the range 40-200° C.

[0039] The compounds of formula III can be prepared by establishedmethods, e.g. according to Hoshino, O., et al., In: The Chemistry ofHeterocyclic Compounds; E. C. Taylor, ed., Volume 38, part 3, page 225et seq., Wiley, New York (1995); or according to Cox, E. D., and Cook,J. M., Chem. Rev. 95 (1995) 1797-1842; or Badia, D., et al., TrendsHeterocycl. Chem. 2 (1991) 1-11.

[0040] (c) A third preferred method for the production of compounds ofthe formula I involves the reaction of compounds of the formula VIII

[0041] wherein A, R¹, R², and X have the meaning defined hereinbeforeand R⁴ is an (1-4C)alkyl group, for example, a methyl or ethyl group,with hydroxylamine in the presence of a suitable base.

[0042] The reaction is carried out in an inert solvent or diluent suchas methanol or ethanol at temperatures between 0° C. and 100° C.,conveniently at or near ambient temperature, and at a pH between 9 and11. A suitable base is, for example, an alcoholate, for example, sodiummethylate.

[0043] (d) Those compounds of the formula I wherein one of thesubstituents is an amino group are prepared by the reduction of aderivative of the formula I wherein the substituent is a nitro group.The reduction may conveniently be carried out by any of the manyprocedures known for such a transformation. The reduction may be carriedout, for example, by the hydrogenation of a solution of the nitrocompound in an inert solvent or diluent as defined hereinbefore in thepresence of a suitable metal catalyst such as palladium or platinum. Afurther suitable reducing agent is, for example, an activated metal suchas activated iron (produced by washing iron powder with a dilutesolution of an acid such as hydrochloric acid). Thus, for example, thereduction may be carried out by heating a mixture of the nitro compoundand the activated metal in a suitable solvent or diluent such as amixture of water and an alcohol, for example, methanol or ethanol, to atemperature in the range, for example, 50 to 150° C., conveniently at ornear 70° C.

[0044] (e) Those compounds of the formula I wherein one of thesubstituents is an (1-4C)alkanoylamino group, are prepared by acylationof a derivative of the formula I wherein the substituent is an aminogroup. A suitable acylating agent is, for example, any agent known inthe art for the acylation of amino to acylamino, for example an acylhalide, for example an alkanoyl chloride or bromide, conveniently in thepresence of a suitable base, as defined hereinbefore, an alkanoic acidanhydride or mixed anhydride, for example acetic anhydride or the mixedanhydride formed by the reaction of an alkanoic acid and analkoxycarbonyl halide, for example an alkoxycarbonyl chloride, in thepresence of a suitable base as defined hereinbefore. In general theacylation is carried out in a suitable inert solvent or diluent asdefined hereinbefore and at a temperature, in the range, for example,−30 to 120° C., conveniently at or near ambient temperature.

[0045] According to a further aspect of the invention there is provideda pharmaceutical composition which comprises a tetrahydropyridinederivative of the formula I, or a pharmaceutically-acceptable saltthereof, as defined hereinbefore in association with apharmaceutically-acceptable diluent or carrier. The composition may bein a form suitable for oral administration, for example as a tablet orcapsule, for parenteral injection (including intravenous, subcutaneous,intramuscular, intravascular or infusion) as a sterile solution,suspension or emulsion, for topical administration as an ointment orcream or for rectal administration as a suppository. In general theabove compositions may be prepared in a manner using conventionalexcipients. The tetrahydropyridine will normally be administered to awarm-blooded animal at a unit dose within the range 5-5000 mg per squaremeter body area of the animal, i.e. approximately 0.1-100 mg/kg, andthis normally provides a therapeutically-effective dose. A unit doseform such as a tablet or capsule will usually contain, for example 1-250mg of active ingredient. Preferably a daily dose in the range of 1-50mg/kg is employed. However the daily dose will necessarily be varieddepending upon the host treated, the particular route of administration,and the severity of the illness being treated. Accordingly the optimumdosage may be determined by the practitioner who is treating anyparticular patient.

[0046] According to a further aspect of the present invention there isprovided a tetrahydropyridine derivative of the formula I as definedhereinbefore for use in a method of treatment of the human or animalbody by therapy. It was surprisingly found that the compounds of thepresent invention possess anti-cell-proliferation properties which arebelieved to arise from their histone deacetylase inhibitory activity.Accordingly the compounds of the present invention provide a method fortreating the proliferation of malignant cells. Accordingly the compoundsof the present invention are useful in the treatment of cancer byproviding an anti-proliferative effect, particularly in the treatment ofcancers of the breast, lung, colon, rectum, stomach, prostate, bladder,pancreas and ovary. In addition, the compounds according to the presentinvention will possess activity against a range of leukemias, lymphoidmalignancies and solid tumors such as carcinomas and sarcomas in tissuessuch as the liver, kidney, prostate and pancreas.

[0047] Thus according to this aspect of the invention there is providedthe use of a tetrahydropyridine derivative of the formula I, or apharmaceutically-acceptable salt thereof, as defined hereinbefore in themanufacture of a medicament for use in the production of ananti-cell-proliferation effect in a warm-blooded animal such as man.

[0048] According to a further feature of this aspect of the inventionthere is provided a method for producing an anti-cell-proliferationeffect in a warm-blooded animal, such as man, in need of such treatmentwhich comprises administering to said animal an effective amount of atetrahydropyridine derivative as defined hereinbefore.

[0049] The anti-cell-proliferation treatment defined hereinbefore may beapplied as a sole therapy or may involve, in addition to the compoundsof the invention, one or more other anti-tumor substances, for examplethose selected from, for example, mitotic inhibitors, for examplevinblastine; allylating agents, for example cis-platin, carboplatin andcyclophosphamide; inhibitors of microtubule assembly, like paclitaxel orother taxanes; antimetabolites, for example 5-fluorouracil,capecitabine, cytosine arabinoside and hydroxyurea, or, for example,intercalating antibiotics, for example adriamycin and bleomycin;immunostimulants, for example trastuzumab; DNA synthesis inhibitors,e.g. gemcitabine; enzymes, for example asparaginase; topoisomeraseinhibitors, for example etoposide; biological response modifiers, forexample interferon; and anti-hormones, for example antioestrogens suchas tamoxifen or, for example antiandrogens such as(4′-cyano-3-(4-fluorophenylsulphonyl)-2-hydroxy-2-methyl-3′-(trifluoromethyl)-propionanilide,or other therapeutic agents and principles as described in, for example,DeVita, V. T., Jr., Hellmann, S., Rosenberg, S. A.; In: Cancer:Principles & Practice of Oncology, 5^(th) ed., Lippincott-RavenPublishers (1997). Such conjoint treatment may be achieved by way of thesimultaneous, sequential or separate dosing of individual components ofthe treatment. According to this aspect of the invention there isprovided a pharmaceutical product comprising a tetrahydropyridinederivative of the formula I as defined hereinbefore and an additionalanti-tumor substance as defined hereinbefore for the conjoint treatmentof cancer.

[0050] The invention will now be illustrated in the followingnon-limiting examples in which, unless otherwise stated:

[0051] (i) evaporations were carried out by rotary evaporation in vacuoand work-up procedures were carried out after removal of residual solidssuch as drying agents by filtration;

[0052] (ii) operations were carried out at ambient temperature, that isin the range 18-25° C. and under an atmosphere of an inert gas such asargon or nitrogen;

[0053] (iii) column chromatography (by the flash procedure) and highpressure liquid chromatography (HPLC) were performed on Merck Kieselgelsilica or Merck Lichroprep RP-18 reversed-phase silica obtained from E.Merck, Darmstadt, Germany;

[0054] (iv) yields are given for illustration only and are notnecessarily the maximum attainable;

[0055] (v) melting points were determined using a Mettler SP62 automaticmelting point apparatus, an oil-bath apparatus or a Kofler hot plateapparatus;

[0056] (vi) the structures of the end-products of the formula I wereconfirmed by nuclear (generally proton) magnetic resonance (NMR) andmass spectral techniques (Micromass Platform II machine using APCI orMicromass Platform ZMD using electrospray);

[0057] (vii) intermediates were not generally fully characterized andpurity was assessed by thin layer chromatography.

EXAMPLE 1

[0058]

[0059] 8-(3,4-Dihydro-1H-isoquinolin-2-yl)-octanoic Acid Hydroxyamide

[0060] (a) In an ice bath, 14 ml triethylamine was added to a suspensionof 3.2 g (20 mmol) O-benzylhydroxylamine hydrochloride in 150 mldichloromethane. Stirring was continued until the solution became clear.Then, 4.5 g (20 mmol) omega-bromo octanoic acid was added, followed by5.6 g (22 mmol) bis-(2-oxo-3-oxazolidinyl)-phosphorylchloride. Stirringwas continued at ambient temperature for 18 h. The solution wasextracted twice with 150 ml each of 1M aqueous hydrochloric acid andtwice with 150 ml each of 1M aqueous sodium bicarbonate. The organicsolvent was removed i. vac. to give 5.1 g (78%) of 8-bromo-octanoic acidbenzyloxy-amide as a colorless oil. MS: 330 (MαH⁺).

[0061] (b) A solution of 0.39 ml (3.12 mmol)1,2,3,4-tetrahydroisoquinoline, 1.08 g (3.3 mmol) 8-bromo-octanoic acidbenzyloxy-amide, and 0.46 g (3.3 mmol) potassium carbonate in 12 mlacetonitrile was heated to reflux for 2 h. After cooling to ambienttemperature, water was added and extracted with ethyl acetate. Theorganic phase was washed with water, dried over sodium sulfate,filtered, and the solvent was evaporated. The residue was purified byreversed phase HPLC using methanol as eluent. There was thus obtained 1g (84%) 8-(3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxy-amide as a colorless oil. MS: 381 (M+H^(+).)

[0062] (c) 200 mg (0.53 mmol)8-(3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acid benzyloxy-amide in 30ml methanol was hydrogenated for 1 h in the presence of palladium onbarium sulfate at ambient temperature and pressure. The catalyst wasremoved by filtration and the solvent was evaporated. There was thusobtained 150 mg (98%) 8-(3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidhydroxyamide as an amorphous solid. MS: 291 (M+H⁺).

EXAMPLE 2

[0063]

[0064] 8-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic AcidHydroxyamide

[0065] (a) In a manner analogous to that of example 1(b),8-bromo-octanoic acid benzyloxy-amide (example 1(a); 0.3 g, 1.3 mmol)was reacted with 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinehydrochloride (0.43 g, 1.3 mmol) in the presence of potassium carbonate(0.18 g, 1.4 mmol) and DMF as solvent to give8-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide as an almost colorless wax (yield 0.28 g, 49%; purifiedby column chromatography using silica gel and ethyl acetate: methanol9:1 as an eluent). MS (M+H⁺)=441.

[0066] (b) In a manner anologous to that of example 1(c),8-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide was hydrogenated to give the title compound in 98% yieldas an amorphous solid. MS (M+H⁺) 351.

EXAMPLE 3

[0067]

[0068]8-(1-isopropyl-6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoicAcid Hydroxyamide

[0069] (a) In a manner analogous to that of example 1(b),8-bromo-octanoic acid benzyloxy-amide (example 1 (a); 0.3 g, 1.1 mmol)was reacted with1-isopropyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline hydrochloride(0.3 g, 1.1 mmol) in the presence of potassium carbonate (0.15 g, 1.1mmol) and DMF as solvent to give8-(1-isopropyl-6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoicacid benzyloxyamide as an almost colorless wax (yield 0.1 g, 20%;purified by column chromatography using silica gel and ethyl acetate aseluent). MS (M+H⁺)=483.

[0070] (b) In a manner anologous to that of example 1(c),8-(1-isopropyl-6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoicacid benzyloxyamide was hydrogenated to give the title compound as anamorphous solid. MS (M+H⁺)=393.

EXAMPLE 4

[0071]

[0072]8-(6,7-dimethoxy-3-methyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidhydroxyamide

[0073] (a) In a manner analogous to that of example 1(b),8-bromo-octanoic acid benzyloxy-amide (example 1(a); 0.7 g, 2.1 mmol)was reacted with 6,7-dimethoxy-3-methyl-1,2,3,4-tetrahydroisoquinolinehydrochloride (0.5 g, 2.1 mmol) in the presence of potassium carbonate(0.3 g, 2.2 mmol) and DMF as solvent to give8-(6,7-dimethoxy-3-methyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide as an almost colorless wax (yield 0.35 g, 37%; purifiedby column chromatography using silica gel and ethyl acetate:methanol=95:5 as an eluent). MS (M+H⁺)=455.

[0074] (b) In a manner analogous to that of example 1(c),8-(6,7-dimethoxy-3-methyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide was hydrogenated to give the title compound in 98% yieldas an almost colorless oil. MS (M+H⁺)=365.

EXAMPLE 5

[0075]

[0076] 8-(6,7-Diethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic AcidHydroxyamide

[0077] (a) In a manner analogous to that of example 1(b),8-bromo-octanoic acid benzyloxy-amide (example 1(a); 0.38 g, 1.2 mmol)was reacted with 6,7-diethoxy-1,2,3,4-tetrahydroisoquinolinehydrochloride (0.3 g, 1.2 mmol) in the presence of potassium carbonate(0.16 g, 1.2 mmol) and DMF as solvent to give8-(6,7-diethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide as an almost colorless wax (yield 0.15 g, 27%; purifiedby column chromatography using silica gel and ethyl acetate:methanol=9:1 as an eluent). MS (M+H⁺)=469.

[0078] (b) In a manner anologous to that of example 1(c),8-(6,7-diethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide was hydrogenated to give the title compound in 98% yieldas an amorphous solid. MS (M+H⁺)=379.

EXAMPLE 6

[0079]

[0080]8-(6,7-dimethoxy-1-phenyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic AcidHydroxyamide

[0081] (a) In a manner analogous to that of example 1(b),8-bromo-octanoic acid benzyloxy-amide (example 1(a); 0.3 g, 1.1 mmol)was reacted with 6,7-dimethoxy-1-phenyl-1,2,3,4-tetrahydroisoquinolinehydrochloride (0.32 g, 1 mmol) in the presence of potassium carbonate(0.14 g, 1 mmol) and DMF as solvent to give8-(6,7-dimethoxy-1-phenyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide as an amorphous solid (yield 0.12 g, 23%; purified bycolumn chromatography using silica gel and ethyl acetate: heptane=1:1 asan eluent). MS (M+H⁺)=517.

[0082] (b) In a manner anologous to that of example 1(c),8-(6,7-dimethoxy-1-phenyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidbenzyloxyamide was hydrogenated to give the title compound in 98% yieldas an amorphous solid. (M+H⁺)=427.

EXAMPLE 7

[0083]

[0084] 8-(1,3,4,9-tetrahydro-β-carbolin-2-yl)-octanoic Acid Hydroxyamide

[0085] (a) In a manner analogous to that of example 1(b),8-bromo-octanoic acid benzyloxy-amide (example 1(a); 0.5 g, 1.5 mmol)was reacted with 1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole (0.25 g, 1.4mmol) in the presence of potassium carbonate (0.2 g, 1.4 mmol) and DMFas solvent to give 8-(1,3,4,9-tetrahydro-β-carbolin-2-yl)-octanoic acidbenzyloxyamide as an amorphous solid (yield 0.18 g, 30%; purified bycolumn chromatography using silica gel and ethyl acetate as eluent). MS(M+H⁺)=420.

[0086] (b) In a manner anologous to that of example 1(c),8-(1,3,4,9-tetrahydro-β-carbolin-2-yl)-octanoic acid benzyloxyamide washydrogenated to give the title compound in 98% yield as an amorphoussolid. MS (M+H⁺)=330.

EXAMPLE 8

[0087] In an analogous manner to that described in the examples 1-7 thefollowing compounds are prepared:

[0088] (a) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-heptanoic acidhydroxyamide

[0089] (b) 6-(3,4-Dihydro-1H-isoquinolin-2-yl)-hexanoic acidhydroxyamide

[0090] (c) 8-(3,4-Dihydro-6-phenyl-1H-isoquinoline-2-yl)-octanoic acidhydroxamide

[0091] (d) 8-(3,4-Dihydro-7-phenyl-1H-isoquinolin-2-yl)-octanoic acidhydroxyamide

[0092] (e)8-(1-Trifluoromethyl-1,3,4,9-tetrahydro-β-carbolin-2-yl)-octanoic acidhydroxyamide

[0093] (f)8-(6-Fluoro-1,3,4,5-tetrahydro-pyrido[4,3-b]indol-2-yl)-octanoic acidhydroxyamide

[0094] (g) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-5-methyl-heptanoic acidhydroxyamide

[0095] (h) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-4-methyl-heptanoic acidhydroxyamide

[0096] (i) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-3-methyl-heptanoic acidhydroxyamide

[0097] (j) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-2-methyl-heptanoic acidhydroxyamide

[0098] (k) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-2-chloro-heptanoic acidhydroxyamide

[0099] (l) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-2,2-dimethyl-heptanoicacid hydroxyamide

[0100] (m) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-2,2-dichloro-heptanoicacid hydroxyamide

[0101] (n) 8-(3,4-Dihydro-1H-isoquinolin-2-yl)-2-methyl-octanoic acidhydroxyamide

[0102] (o) 6-(3,4-Dihydro-1H-isoquinolin-2-yl)-2-methyl-hexanoic acidhydroxyamide

[0103] (p) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-4-oxa-heptanoic acidhydroxyamide

[0104] (q) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-3-methyl-4-oxa-heptanoicacid hydroxyamide

[0105] (r) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-3-oxa-heptanoic acidhydroxyamide

[0106] (s) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-3-oxa-5cis-heptenoic acidhydroxyamide

[0107] (t) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-3-oxa-5trans-heptanoicacid hydroxyamide

[0108] (u) 7-(3,4-Dihydro-1H-isoquinolin-2-yl)-2-methyl-3-oxa-heptanoicacid hydroxyamide

EXAMPLE 9

[0109] Evaluation of HDAC Inhibitory Properties of the Compounds of theInvention

[0110] To determine the HDAC inhibitory properties of the compounds ofthe invention an assay was performed using an aminocoumarin derivativeof an omega-acetylated lysine as substrate for the enzyme. This assayhas been described in detail by Hoffmann, K., et al., Nucleic Acids Res.27 (1999) 2057-2058. Using the protocol described therein, theinhibitory effect of representative compounds was determined at aconcentration of 10 nM. The observed inhibition rates for selectedcompounds are shown in Table 1: TABLE 1 Title compound of example NoInhibitory effect at 10 nM in % 1 54 5 26 6 26 7 26

[0111] List of References

[0112] Badia, D., et al., Trends Heterocycl. Chem. 2 (1991) 1-11

[0113] Cox, E. D., and Cook, J. M., Chem. Rev. 95 (1995) 1797-1842

[0114] DeVita, V. T., Jr., Hellmann, S., Rosenberg, S. A.; In: Cancer:Principles & Practice of Oncology, 5^(th) ed., Lippincott-RavenPublishers (1997)

[0115] Hoffmann, K., et al., Nucleic Acids Res. 27 (1999) 2057-2058

[0116] Hoshino, O., et al., In: The Chemistry of Heterocyclic Compounds;E. C. Taylor, ed., Volume 38, part 3, page 225 et seq., Wiley, New York(1995)

[0117] Koyama, Y., et al., Blood 96 (2000) 1490-1495

[0118] Marks, P. M., J. Natl. Cancer Inst. 92 (2000) 1210-1216

[0119] U.S. Pat. No. 5,369,108

[0120] WO 98/55449

1. A compound of formula I

(a) denotes a phenyl group which may be unsubstituted or substitutedwith 1, 2 or 3 substituents independently selected from a halogen atom,an (1-4C)alkyl-, trifluoromethyl-, hydroxy-, (1-4C)alkoxy-, benzyloxy-,(1-3C)alkylenedioxy-, nitro-, amino-, (1-4C)alkylamino-,di[(1-4C)alkyl]amino-, (1-4C)alkanoyl-amino-, or a phenyl group, whichmay be unsubstituted or substituted by 1, 2, or 3 substituentsindependently selected from a chlorine atom, an (1-4C)alkyl-,trifluoromethyl-, hydroxy-, (1-4C)alkoxy-, (1-3C)alkylenedioxy-, nitro-,amino-, (1-4C)alkylamino-, di[(1-4C)alkyl]amino-, and a(1-4C)alkanoylamino group, or (b) denotes an indolyl group which may beunsubstituted or substituted with 1, 2 or 3 substituents independentlyselected from a halogen atom, an (1-4C)alkyl-, trifluoromethyl-,hydroxy-, (1-4C)alkoxy-, benzyloxy-, (1-3C)alkylenedioxy-, nitro-,amino-, (1-4C)alkylamino-, di[(1-4C)alkyl]amino-, or a(1-4C)alkanoylamino-group, R¹ and R² are the same as or different fromeach other and are a hydrogen atom, an (1-4C)alkyl-, a trifluoromethylgroup, or an aryl group, X is a straight chain alkylene group comprising5, 6, or 7 carbon atoms, wherein one CH₂ group may be replaced by anoxygen or a sulfur atom, or wherein 2 carbon atoms form a C═C doublebond, and which is either unsubstituted or substituted by one or twosubstituents selected from (1-4C)alkyl and halogen atoms, theirenantiomers, diastereoisomers, racemates and mixtures thereof andpharmaceutically acceptable salts.
 2. A compound of formula I accordingto claim 1 wherein

is a phenyl group which may be unsubstituted or substituted with 1 or 2substituents independently chosen from hydroxy-, (1-4C)alkoxy,benzyloxy, or a phenyl group,

is an indolyl group which may be unsubstituted or substituted with ahalogen atom, R¹ and R² are the same as or different from each other andare a hydrogen atom, a (1-4C)alkyl-, a trifluoromethyl group or a phenylgroup, X is a straight chain alkylene group comprising 5, 6, or 7 carbonatoms, wherein one CH₂ group may be replaced by an oxygen or a sulfuratom, or wherein 2 carbon atoms form a C═C double bond, and which iseither unsubstituted or substituted by one or two substituents selectedfrom a methyl group, fluorine, or chlorine atoms, their enantiomers,diastereoisomers, racemates and mixtures thereof and pharmaceuticallyacceptable salts.
 3. A compound of formula I according to claims 1 or 2selected from the group consisting of8-(3,4-Dihydro-1H-isoquinolin-2-yl)-octanoic acid hydroxyamide8-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidhydroxyamide8-(1-isopropyl-6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoicacid hydroxyamide8-(6,7-dimethoxy-3-methyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidhydroxyamide 8-(6,7-Diethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-octanoicacid hydroxyamide8-(6,7-dimethoxy-1-phenyl-3,4-dihydro-1H-isoquinolin-2-yl)-octanoic acidhydroxyamide 8-(1,3,4,9-tetrahydro-β-carbolin-2-yl)-octanoic acidhydroxyamide.
 4. Process of manufacturing a compound of formula Iaccording to claims 1 to 3 by reacting a compound of formula III

wherein A, R¹ and R² have the meaning defined in claim 1 with a compoundof formula IV Z-X—CONH—O—Y  (IV) wherein Z is a displaceable group, Y isa protecting group and X has the meaning as defined in claim 1, in thepresence of a suitable base, where after the protecting group Y issplitted off by hydrogenolysis.
 5. Pharmaceutical composition containingas active ingredient a compound of formula I according to claims 1 to 3in admixture with a pharmaceutically acceptable excipient or diluent. 6.Use of a compound according to claims 1 to 3 for the preparation of amedicament having histone deacetylase (HDAC) inhibitor activity.
 7. Useof a compound according to claim 6 as an inhibitor of cellproliferation.